“A  STUDY  OF  THE  ELECTROLYTIC 
PREPARATION  OF  HYDROXYLA- 
MINE  HYDROCHLORIDE  AND 
HYDROXYLAMINE  SULPHATE” 

BY 


FULLER  FRANCIS  ROSS 


THESIS 


FOR  THE 


DEG  REE  OF  BACHELOR  OF  SCIENCE 


IN 

CHEMICAL  ENGINEERING 


COLLEGE  OF  LIBERAL  ARTS  AND  SCIENCES 


UNIVERSITY  OF  ILLINOIS 


1,922 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/studyofelectrolyOOross 


/ 922 
H73 


UNIVERSITY  OF  ILLINOIS 


....May....2,6 


THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 



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IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 

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Acknowledgment 


The  writer  desires  to  express  his 
gratitude  to  Dr,  J.  H.  Beedy,  who  has 
aided  in  this  v/ork  hy  his  very  helpful 
suggSstions, 


Index  to  Contents 


Page 

I.  Introduction*  1 

II,  Historical 2 

III,  Purpose  of  the  problem 7 

IV.  Experimental 8 

V.  Conclusion 17 

VI,  Bibliography 16 


A STUDY  0?  THE  ELECTROLYTIC  PREPARATION  OP 
HYSROXYLAI.TIME  HYDROCHLORIDE  MB  HYDROXYLAl^IITE 

SULPHilTE 

Intro Auction 

Electrical  methods  in  reduction  and  oxidation  have  the 
decided  advantage  over  strictly  chemical  methods  in  that  they  are 
more  readily  controlled  "by  adjustment  of  the  potential.  Further- 
more, the  products  are  purer,  since  there  are  no  reduction  or 
oxidation  "by-products  to  "be  removed,  Verj'-  probably,  it  is  the 
element  of  cost,  which  limits  more  extensive  use  of  electrolytic 
methods. 

Numerous  methods  have  been  suggested  for  the  preparation 
of  hydroxiy’-lamine , some  impracticable,  others  with  varying  merits. 
Reduction  of  nitrites,  nitrates,  nitric  acid  and  nitric  oxide  to 
Kydroxylam.ine  have  been  discussed  in  some  dsta>il  by  some  authors. 

In  every  case,  the  methods  are  more  or  less  unsatisfactory  because 
of  small  yields.  Besson  ^ in  1911  claimed  he  had  obtained  the 
compound  by  the  action  of  a silent  dischiarge  upon  moist  ammonia  and 
similarly  in  1909,  Ezio  Comanducii'^  investigated  the  effect  of  an 
electric  discliarge  upon  a mixture  of  ammonia  and  03^gen,  with 
production  of  Hydro xylamine.  Neither  of  these  methods  have  been 
given  much  attention,  but  they  go  to  illustrate  an  extended  use 
of  electrical  methods  in  organic  preparations, 

A great  many  authors  ascribe  the  difficulty  of  preparation 


of  the  amine  to  the  formation  of  by-products  as  aresult  of  the 


According  to  Raschig*^  (1890-)  the  hydrochloride  of 
Hydroxj'l amine  is  obtained  as  follows:  A saturated  solution  of 

sodium  nitrite  (l  mol. ) is  added  to  a solution  of  hydrogen  sodium 
sulphite  (2  mols.  ) in  a cooled  vessel,  and  then  a cold  saturated 
solution  of  potassiumi  chloride  is  added.  After  24  hours  the 
Hydroxylamine  disulphonate  separates.  This  salt  is  boiled  in  water 
several  hours.  After  cooling  the  Ifydroxylamine  sulphate  separates 
out  and  is  converted  into  the  hydrochloride  form  with  bariim 
chloride* 

The  same  authors,  Divers  and  Haga^,  9 years  later  (1896) 
claimed  that  Sodium  nitrite  in  the  presence  of  Sodium  carbonate 
could  be  reduced  to  the  amine  by  use  of  Sulphur  dioxide  gas  if  a 
temperature  of  2-3  degrees  centigrade  below  zero  was  maintained,  at 
which  temperature  hydro xj^l amine  will  not  be  deccmiposed  by  the 
sulphur  dioxide  present.  The  solution  of  oximidosulphonate  is 
hydrolyzed  to  NH2OH  by  a few  drops  of  H2SO4  after  two  days  maintain- 
ing a temperature  of  80-85°,  Besides  these,  C,  F.  Boehringer  and 

p 

Sdhne°  and  F,  B,  Ahrens  have  attemipted  to  carry  out  efficient 
electrolytic  methods  for  the  preparation  of  the  salts  of  Bydroxy- 
lam.ine, 

Ahrens^  (1903)  reduced  50  percent  llitric  acid  in  a 50^ 
Sulphuric  acid  solution  using  a cooled  lead  cylinder  for  an  anode 
and  for  the  cathode  an  amalgamated  lead  cup,  cooled  by  a mixture  of 
salt  and  ice.  He  passed  a current  of  24  amperes  for  tv;o  hours  and 
forty  minutes  after  which  time  the  Hydroxy lamiine  sulplia.te  formed, 
was  removed  from,  the  ca.thode  cup  and  the  sulphate  precipitated  out 
with  barium  chloride.  The  converted  Hydro xj'-l amine  hydrochloride 
Vt’as  then  filtered  from  the  bariumi  sulphate  and  evaporated  to 


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-4 


dryness  under  diminished  pressure*  The  salt  was  purified  from  the 
ammonium  chloride  hy  several  crystallizations  from  hot  water  equal 
to  1/2  of  its  weight.  Ahrens  claimed  a yield  of  80^  of  the  Nitric 
acid  used.  His  v/ork  carried  out  with  a zinc  cathode  shov^ed  a yield 
of  a 15-25^  solution  of  Hydroxj’’lamine  salt  using  a solution  of 
nitric  acid,  2 amperes  current  and  maintaining  a temperature  of  0 

degrees  centigrade. 

"5  4 

Tafel'  * , a.hout  the  same  time,  employed  practically  the 
same  method  as  Ahrens,  claiming  a 75-80^  yield  of  Hydroxylamine 
hydrochloride,  based  on  the  Nitric  acid  used.  One  precaution  out- 
lined  was  that  in  the  addition  of  the  barium  chloride  solution  to 
the  Hydroxylamine  sulphate  solution  care  should  be  taken  to  retain 
a temperature  of  30  -40  degrees  centigra.de.  The  same  procedure  was 
carried  out  for  filtration  and  crystallization  of  the  hydrochloride 
as  was  outlined  above,  in  Ahrens*  work. 

Otto  Flaschner  ^^(1907}  studied  the  electro -reduction  of 
Hydroxylamine  and  of  nitric  acid  using  various  cathode  materials 
v;ith  rather  varied  results.  He  em.phasized  the  fact  that  different 
metals  as  cathodes  gave  different  potentials  and  in  each  case  the 
extent  of  reduction  differed.  A high  potential  seemed  conducive 
to  the  production  of  Hydroxylam.ine  while  the  low  potential  resulted 
in  the  usual  formation  of  a large  quantity  of  ammonia. 

The  latest  work  of  any  im.portance  has  been  done  by 
E.  P.  Schoch''  and  P..  H.  Pritchett  (1916),  The3?  developed  a method 
for  preparation  of  the  Hydroijqylamine  hydrochloride  directly  v/ithout 
the  intermediate  barium  chloride  precipitation.  They  developed  a 
method  using  an  am.algamated  lead  cathode  and  a porous  cell  enclosing 
a lead  rod  for  an  anode.  Fifty  percent  hydrochloric  acid  was 


placed  in  the  cathode  compartment  and  fifty  percent  sulphuric  acid 
in  the  anode  chamber.  By  the  addition  of  small  quantities  of  fifty 
percent  nitric  acid  to  the  cathode  compartment,  the  investigators 
were  able  to  obtain  the  Hydro:^’lamine  hydrochloride  directly.  A 
vacuum  distillation  to  dryness  and  a recrystallization  with 
absolute  alcohol  gives  an  80^  yield,  the  20^  loss  being  attributed 
to  the  evolution  of  arrmonia  or  the  formation  of  ammonium  compounds. 
There  was  a certain  amount  of  ammonium  chloride  in  the  crj^stallized 
hydrochloride.  Impest igat ion  showed;  Ethyl  alcohol  at  15®  C. 
dissolves  44.3  grams.  Hydro :^ylam,ine  hydrochloride.  Alcohol  at  the 
same  temperature  dissolves  6.2  grair.s  ammonia  chloride.  In  this 
work  a current  of  50  amperes  ws.s  passed  through  the  cell  for  three 
hours.  The  temperature  was  maintained  at  15  degrees  or  less. 

Various  m.echanical  ideas  were  brought  into  use  such  as  a vacuum 
cylinder  arranged  to  keep  the  cathode  solution  circulating  through 
a cooling  mixture.  According  to  more  recent  information,  it  has 
been  found  that  this  method  has  not  been  nearly  as  successful  as 
originally  described.  An  attempted  duplication  of  the  work  by  the 
authors  themselves  has  resulted  in  very  low  yields, 

M.  A,  Beeson  published  his  work  on  the  study  of  an 
electric  discharge  on  wet  and  on  dry  ammonia  gas.  He  found  that  the 
effect  of  an  electric  discharge  on  dry  ammonia  resulted  in  the 
partial  formation  of  nitrogen  and  hydrogen.  The  ammonia  gas  is 
dried  by  passing  through  a long  column  of  fused  potassium  hydroxide 
then  refrigerated  and  subjected  to  the  discharge,  thus  yielding  the 
products  mentioned  above.  He  found  that  the  electrical  discharge 
did  not  react  in  a similar  manner  in  the  presence  of  moist 
ammonia,  but  decomposed  into  Hydro xjriamine  and  hydrogen  according 


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to  the  following  reaction:  NH3  + H2O  = Ha+  ITHaOH 

Besson  confirmed  the  presence  of  Hydro :xylarnine  by  reducing  a copper 
sulphate  solution. 

So  far,  we  have  discussed  the  various  important  methods  of 
electrolytic  preparation  of  Hydroxy lamine  salts  and  have  only  men- 
tioned other  methods  that  are  related  to  the  problem.  Since  this 
present  work  makes  use  of  an  Illium  cathode,  a short  discussion  of 
the  alloy  seems  apropos. 

Illium  is  an  acid-resisting  alloy  invented  by  Professor 
S,  W,  Parr^^ of  this  University.  It  has  several  compos- 
itions but  possessing  an  important  property  in  each  case-it*s 
resistance  to  corrosion  by  acids  such  as  sulphuric  and  nitric  acids. 
It  is  given  the  general  formula; 

SO.Sbfo  nickel 
21,07  Chromium 
2.13  Tungsten 
1,09  Aluminium 
,98  Manganese 
6.42  Copper 
,76  Iron 
4 . 67  Mo  lyb  den  urn 
1.04  Silicon 

It  possesses  a high  electrical  resistance.  Very  little  detail  has 
been  printed  upon  the  various  properties  of  Illium.  Assuiaing  that 
the  alloy  possessed  the  property  of  electrical  conductance,  it  was 
thought  possible  to  utilize  it  as  an  electrode  in  the  ordinary  type 
of  electrolytic  reduction  reactions. 

According  to  Allmand  , the  effect  of  the  cathode  material 
on  the  course  of  reduction  is  two -fold, 

1,  Different  cathodes  catalyse  the  reaction  in  such  a 
manner  that  reduction  can  take  place  with  a far  less  negative  cathode 
potential  at  some  cathodes  than  at  others. 


-7- 

2.  At  the  same  cathode  potential,  the  current  density 

can  vary, 

A change  in  the  surface  area  of  the  cathode  would  change  the  current 
density  and  possibly  give  a more  desirable  potential  for  reduction. 

In  other  words,  when  the  surface  area  of  the  electrode  is 
altered,  the  strength  of  the  current  remaining  the  same,  the  number 
of  ions  discharged  at  unit  surface  varies  in  direct  proportion. 
Therefore,  by  selecting  a suitable  electrode,  it  is  possible  to  cause 
the  concentration  of  the  ions  to  vary  within  wide  limits, 

III 

Purpose  of  the  Problem 

Some  authors  have  stated  that  Hydroxylamine  was  prepared 
when  the  temperature  \vas  30-40degrees  centigrade  (Tafel'^), 

Schoch  and  Pritchett  kept  the  temperature  about  15  degrees  or  less. 
It  was  thought  desirable  to  obtain  some  a.dditional  information,  then, 
about  temperature  regulation  in  this  preparation. 

Since  Illium  has  never  been  used  for  electrolytic  work  an 
investigation  of  its  availability  for  this  purpose  suggested  itself. 
By-products,  or  further  reduction  products  of  Hydroxj-'l- 
araine  such  as  ammonia  and  ammonium  salts,  keeps  the  maximum  yield 
of  the  amine  at  80^.  If  this  process  could  be  perfected  so  as  to 
prevent  any  further  reduction  than  Hydroxylamine,  the  yield  could  be 
appreciably  increased. 

Reduction  of  nitric  acid  is  the  usual  practice.  It  would 
be  interesting  therefore  to  study  its  electrolytic  reduction  in  some- 
what the  same  manner  as  before  and  also  to  study  the  reduction  of 
nitrites  which  is  already  one  stage  closer  to  the  formation  of  the 


M0M 


amine  than  nitrates. 


IV 

Experimental 


GEITERAL  liCETIIOB 


Solutions 


Anode  (Porous  cell)-  40  cc  bO%  H2SO4 
Cathode  (outer  glass  cell)-  lOOcc  bO%  H2SO4 
Cathode  (outer  glass  cell)-  15cc  bO%  HNO3 


Diagram  and  setting-  next  page. 


Procedure 


The  general  method  of  reduction  of  nitric  acid  in  the 
presence  of  sulphuric  acid  was  attempted  in  which  the  desired 
product  should  he  Hydroxylamine  sulphate.  Twenty  amperes  current 
was  passed  through  the  Cell  for  1 1/4  hours.  A lead  tube  3/8  inches 
in  diameter  and  2 feet  long  was  coiled  into  a spiral  so  that  it  just 
fit  into  the  anode  chamber,  a porous  cup  1 1/2  inch  in  diameter  and 
3 inches  high.  Water  was  passed  through  the  tube,  the  temperature 
being  18®  Centigrade,  Around  the  cathode  compartment,  a m.ixture  of 
salt  and  ice  was  used  to  aid  in  keeping  down  the  temperature.  The 
cathode  electrode  was  an  Illium  lug  of  7.599  square  centimeters 
surface  area.  The  cathode  chamber  was  a glass  cylinder  3 inches  in 
diameter  and  4 inches  high.  The  15  cubic  centimeters  of  nitric  acid 
was  added  in  about  15  minutes,  or  at  the  rate  of  1 cubic  centimeter 
per  minute.  After  1 1/4  hours,  the  reaction  was  stopped.  It  was 
observed  that  the  brown  fumes  of  nitrogen  (HO2 ) issued  from  the 
anode  during  the  reaction,  but  more  actively  at  the  beginning  of  the 
reaction  than  near  the  end.  The  lead  anode  was  eaten  through 


VIPI^fG  Di/2&G/^ra 
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Wdt-mr-  Cooleei  L.e«ct  t^rrocfe. 


I 


completely  and  lead  sulphate  deposited  in  the  bottom  of  the  cell 
due  to  the  oxidation  effect  of  nitrogen  dioxide  in  the  presence  of 
the  sulphuric  acid  solution.  The  brown  ring  test  with  ferrous 
sulphate  formed  the  unstable  FeS04*^0,  verifying  the  presence  of 
unreduced  nitric  acid  or  at  least  no  further  reduction  than  nitrous 
acid.  The  usual  steps  in  this  rSduction  are; 

MO  3 = MO2  = ITH2OH  = ITH3 

The  increase  of  temperature  around  the  cathode  as  the  process 
continued  followed  the  graph  as  shown  on  the  next  page.  Tests  with 
Fehling’s  solution  showed  the  absence  of  Hydroxylamine.  It  is 
evident  that  the  procedure  as  carried  out  was  above  the  decomposition 
temperature  of  Hydroxylamine , therefore  eliminating  the  possibility 
of  its  preparation, 

COHTROL  OF  TEI.fPERATURE 

The  next  attempt  to  control  temperature  prompted  a slight 
change  of  set-up.  In  this  case  the  lead  anode  coil  was  placed  around 
the  porous  cell  and  the  porous  cell  was  made  the  cathode  compartment. 
The  quantities  used; 

Anode  - 200 cc  b0%  H2SO4 
Cathode-  30 cc  50^  H2SO4 
Cathode  3.2  grams,  HITO3  (4-5cc  50;^) 

The  current  was  reduced  to  ten  amperes.  The  temperature  of  the 
water  through  the  lead  tube  was  I6  degrees  Centigrade.  An  ice  and 
salt  mixture  surrounded  the  anode  chamber.  The  temperature  was 
much  mo?.’e  under  control  in  this  case  than  before  as  will  -be  seen 
by  the  graph.  The  solution  of  Hydroxylamine  sulphate  was  treated 
with  barium  chloride  solution  (50^)  and  the  sulphate  precipitated 


( 


“10 


out,  leaving  the  hydrochloride  of  Hydroxyl  amine  in  sol^ition.  This 
solution  was  evaporated  almost  to  dryness  and  the  crystals  removed 
as  formed.  Treatment  with  95^  ethyl  alcohol  extracted  the  hydro- 
chloride crj'stals  or  at  least  v/hat  appeared  to  be  the  crystals  of 
the  salt.  Crystals  of  ammonium,  chloride  remain  comparatively 
undissolved.  The  insoluble  crystalline  residue  was  filtered  off. 

The  crj^stals  treated  with  sodium  hydroxide  gave  off  abundant 
ammonia  fumes,  confirming  the  statements  of  some  authors  that  the 
electrolytic  reduction  of  nitric  acid  goes  over  completely  into 
ammonia  and  ammoniumi  compounds.  The  alcoholic  solution,  upon 
evaporation  in  vacuum*  on  the  water  bath,  gave  additional  crystals 
which  also  gave  the  test  for  ammonia.  Hehling’s  solution  was  not 
reduced  by  the  crystals  of  either  the  first  or  second  batch.  The 
crystals  were  distinctly  acid  and  gave  off  an  odor  of  chlorine. 

A partic-1  explanation  for  not  obtaining  Hydroxy lamine  might  be  again 
attributed  to  the  temperature  which  was  still  too  high  around  the 
cathode  to  favor  its  formation.  The  lowest  temperature  during  the 
run  was  22®  Centigrade,  with  an  average  temperature  of  appro xim*ately 
39°  Centigrade.  The  decomposition  of  Kydrosylamdne  takes  place 
at  33®  Centigrade, 

GREATEST  HEATIHG  AROUHi:  THJi!  CATHODE 
Apparently  the  highest  heating  area  is  in  the  cathode 
compartment.  This  v/as  found  to  be  true  not  only  when  the  cathode 

was  in  the  inner  cell  and  surrounded  by  the  lead  anode  water  coil, 

to 

but  also  when  the  ca,thode  chamber  was  the  outer  chamber  nex;^the 
ice-salt  mdxture.  The  latter  method  seemed  the  most  promising, 
i.e.  v/ith  the  cathode  cell  as  the  outer  cell. 


-11- 

EFPECT  OF  SLOW  ADDITION  OF  NITRIC  ACID 
A porous  cell  2 inches  in  diameter  and  4 inches  high  was 
substituted  for  the  1 1/2  inch  cell  so  as  to  give  a greater  capacity 
and  reduce  mechanical  difficulties.  Glass  tubes  were  placed  into  the 
ca.thode  chamber  and  an  ice-salt  water  mixture  alloY/ed  to  flow  through 
them  thus  aiding  in  keeping  the  solution  in  the  cathode  cooler  than 
ever  before. 

The  quantities  used 

Anode  - 125  cc,  50^  H2SO4 
Cathode  150  cc.  50^  H2SO4 
Cathode  30  cc.  50^^  HNO3 

In  every  determination  made,  the  nitric  acid  was  added  more  or 
less  rapidly.  Possibly  too  ra,pid  an  addition  of  the  acid  would 
prevent  its  reduction  of  Hydro rylamine.  At  any  rate  very  positive 
brown  ring  tests  showed  the  presence  of  unreduced  nitric  acid  in  the 
cathode  solution.  This  time  care  v/as  taken  to  add  the  acid  drop  by 
drop  at  the  rate  of  1/2  cc,  per  minute.  A current  of  10  amperes  v/as 
passed  through  the  cell  for  two  hours.  The  current  was  allowed  to 
continue  for  one  hour  a.fter  the  last  addition  of  nitric  acid  had 
been  made,  A.fter  the  first  hour,  some  of  the  cathode  solution 
pipetted  out  and  m.ade  alkaline,  gave  an  excellent  reduction  reaction 
(Fehling*s  solution)  confirming  the  presence  of  Hydroxyl amine.  To 
ascertain  just  where  the  reduction  reaction  took  place  in  the  cathode 
cell,  a portion  of  the  solution  farthest  away  from  the  electrode  v/as 
subjected  to  the  brown  ring  test  (FeS04).  The  presence  of  unreduced 
nitrates  or  nitrites  was  confirmed.  No  reduction  of  Fehling^s 
solution  could  be  obtained.  Evidently,  then^ the  reaction  for 


-12- 

reduction  took  place  in  the  immediate  vicinity  of  the  cathode  and 
those  nitrate  or  nitrite  ions  which  were  migrated  did  not  enter  into 
any  reduction  process.  The  lead  anode  v/as  covered  with  a hrown 
lead  dioxide.  Upon  titration  with  2%  potassium  permanganate,  the 
solution  showed  20^  ammonium  hydroxide.  During  electrolytic 
reduction  operations  such  as  we  have  carried  out,  there  is  hydrogen 
evolved  at  the  cathode.  After  two  hours  the  Illium  lug  v/as  covered 
with  a brown  film  and  at  the  same  time  no  m.ore  bubbles  of  liydrogen  or 
of  any  gas  came  off  through  the  liquid.  The  reaction  was  stopped. 
After  an  hour  a repeated  test  v^rith  Fehling’s  solution  gave  negative 
results.  The  probable  reason  for  not  obtaining  Hydroxylamine  again 
was  because  of  the  presence  of  unreduced  nitric  acid  in  the  cathode 
solution  which  reacted  with  the  Hydroxylamine  form.ed,  decomposing  it, 

FACTORS  EFFECTING  STABILITY  OF  HYDRO XYLAI^DTE 

Further  attempts  have  shown  that  the  use  of  two  Illium  lugs 
with  a total  area  of  15  square  centimeters  gave  better  results, 
because  a more  desirable  potential  for  reduction  is  obta,ined. 

The  follow'ing  determiinat ion  was  run  for  three  hours;  1 1/2 
hours  of  that  tim.e  was  taken  in  adding  the  nitric  acid.  The  current 
of  ten  amperes  was  again  used  but  with  a greater  cathode  area  the 
potential  developed  was  different.  The  sarnie  quantities  of  solutions 
were  used  as  in  previous  run.  The  cathode  solution  was  kept  at  a 
temperature  of  12®  - 13®  Centigrade  during  the  run,  A jigger  aided 
in  shaking  up  the  nitric  acid  into  the  solution  as  it  Tvas  added. 

This  solution  tested  positively  for  Hydroxylamine  sulph.a,te  with 
Fehling’s  solution,  both  at  the  lov/  temperature  and  at  ordinarj^  room 
temperature.  This  confirmed  the  stability  of  Hydroxylamine  sulphate 


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when  these  two  factors  are  kept  in  mind: 

1,  Keep  the  temperature  at  15®  Centigrade  or  less, 

2,  Continue  the  electrolysis  for  a considerable  time  aftei 
the  last  addition  of  nitric  acid.  This  seems  to  insure  more  complete 
reduction  of  the  nitric  acid  and  lessens  the  opportunity  of  its 
being  present  in  large  enough  quantities  to  decompose  the  Hydro xy- 
lamine.  How  an  attempt  was  made  to  convert  the  Hydroxylamine 
sulphate  into  the  hydrochloride,  by  a better  method  than  the  old 
barium  chloride  method  used  before.  Eickhoff^^  states  that  if  the 
calculated  quantity  of  barium  chloride  be  added  to  the  Hydroxylamine 
sulphate  solution  and  the  barium  sulphate  removed  by  filtration,  the 
Hydroxylamine  hydro chlo ride  may  be  separated  by  concentration  and 
crystallization.  This  method  is  difficult  to  carry  out,  however, 
and  the  yield  is  always  poor.  If  barium  chloride  is  in  excess, 
double  salts  form  and  then  it  is  not  easy  to  calculate  the  exact 
quantity  of  the  chloride  required  for  neutralization. 

COITVERSIOIT  OE  THE  SULPHATE  TO  THE  HYDROCHLORIDE  THROUGH 

BEHZALDOXIIS 

The  acid  solution  was  neutralized  with  sodium  hydroxide 
keeping  the  temperature  belov/  15®  Centigrade.  Then  100  cubic 
centimeters  of  benza.ldehyde , ice  cold,  was  add.ed  to  the  Hydroxylamine 
sulphate.  The  purpose  of  this  procedure  was  to  form  the  oxim.e  and 
then  to  hydrolyze  the  oxime  with  hydrochloric  acid  giving  the 
aldehyde  again  and  Hydroxylam.ine , Later  attempts  at  hydrolysis  were 
unsatisfactory  as  far  as  conf irmato rj’-  tests  for  Hydroxylamine 
hydrochloride  were  concerned.  The  cause  due  to  the  fact  that  in 
neutralizing  the  solution  with  sodium  hydroxide  the  solution  must 


14- 


have  been  made  alkaline.  If  this  was  true  Hydro xylamine  would  have 
been  liberated  before  it  had  an  opportunity  to  combine  with  the 
aldehyde,  as  the  oxime.  According  to  the  literature,  a large  amount 
of  the  Hydroxylamine  is  lost  even  upon  careful  hydrolysis  of  the 
oxime  in  slightly  acid  or  neutral  solution.  It  is  quite  possible 
to  explain  the  reaction  between  the  amine  and  the  aldehyde  as 
follows,  however 


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Hy  d ro  lamin  e - 

Hydrochloride  Benzaldehyde  Benzaldoxime 

If  Hydro xjj^lamine  hydrochloride  could  be  prepared  in 
electrolytic  cell  directly  without  any  intermediate  steps  such 
barium  chloride  precipitation  or  a hydrolysis  of  an  amine,  the 
method  would  be  invaluable,  Schoch  and  Pritchett  offer  such  a 
and  so  a study  of  the  reduction  of  nitric  acid  in  the  presence 
hydrochloric  acid  instead  of  sulphuric  acid  was  carried  out. 


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of 


DIRECT  PREPARATICH  OE  THE  HYDROCHLORIDE 
The  qu8.ntities  used 

Anode  - 125  cc  50^  H2SO4 

Cathode  150  cc  50^^  HCl 

Cathode  20  cc  50^  H>T0a 


-15- 

A current  of  10  amperes  was  used.  The  temperature  was  kept  at 
11®  - 14®  Centigrade.  Two  hours  was  taken  in  adding  the  nitric  acid 
and  this  was  followed  "by  another  hour  of  electrolysis  to  reduce  the 
nitric  adid  as  completely  as  possible.  It  will  be  observed  that 
sulphuric  acid  was  placed  in  the  anode  chamber  as  before. 

Hydrochloric  acid  would  have  eaten  the  lead  anode  if  it  had  been 
substituted. 

The  final  reduced  solution  gave  the  conf irmato rjr  test  for 
Hydroxylamine  so  the  next  step  was  the  evaporation  under  vacuum  on 
the  water  bath.  It  was  possible  to  only  partially  evaporate  the 
solution,  hov/ever,  upon  analysis,  it  was  found  that  there  Y/ere 
sulphate  ions  present  in  the  salution,  and  this  meant  a high  boiling 
constituent.  The  sulphate  ions  had  migrated  from  the  anode  cell 
and  had  to  be  removed  from  the  mixture  of  IIH2OH.HCI  and  HCl  by 
precipitation  with  barium  chloride.  Again  this  involved  intermediate 
steps  of  precipitation,  filtration  and  re-evaporation.  Apparently 
the  loss  of  Hydroxylamine  was  again  experienced.  If  any  of  the 
nitric  acid  was  present  and  unreduced  it  vfculd  without  doubt 
decompose  the  Hydroxylamine  when  the  solution  was  heated  during 
evapo ration, 

REDUCTION  OE  NITRITES  TO  BENZALDOXIL'ES 
Nitrites  are  one  stage  farther  reduced  than  nitrates 
therefore,  why  would  it  not  be  possible  to  use  all  the  current  energy 
in  the  reduction  process  from  the  nitrite  stage  on  to  the  Hydroxyl- 
amine stage?  At  the  same  time,  if  Hydroxylamine  is  formed  could  it 
not  be  converted  into  benzaldoxime  directly  in  the  cell  and  later 
hydrolyzed  to  give  Hydro x^j’-lamine  hydrochloride? 


-16- 

This  possibility  was  next  considered. 

The  quantities  used 

Cathode  60  cc  50^a  HCl 

70  cc  Benzaldehyde 
15  cc  UalT02  (15  gr,  ) 

Anode  125  cc  50^  H2SO4 

The  temperature  was  higher  for  some  reason  a.nd  was  about  25®  Centi- 
grade, With  a current  of  ten  amperes  flowing  for  t"wo  hours,  a. 
two -layered  solution  was  obtained.  The  benzaldehyde  was  separated 
from  the  hydrochloric  acid  solution.  The  solution  reduced  potassium 
permanganate,  but  did  not  effect  Fehling’s  solution.  It  was  con- 
clusive of  the  absence  of  the  amine.  It  is  understood  that  nitrites 
are  readily  reducable  in  acid  or  neutral  solutions  and  in  fact  we 
find  some  reducing  constituent  present  in  this  case.  Whether  the 
Hydroxylamine  will  combine  with  the  aldehyde  in  acid  solution  is 
very  doubtful.  The  Hydroxylamine,  if  formed,  probably  decomposed 
imm.ediately  because  the  temperature  was  25®  Centigrade  during  the 
run.  Sodium  nitrite  is  very  easily  decomposed  by  an  acid  solution 
setting  free  nitrous  acid  (nitric  and  nitrous  oxides. ) 


-17- 

V. 

Conclusion 

From  the  work  carried  out  we  have  been  able  to  observe  some 
of  the  characteristic  reactions  7/hich  occur  in  the  electrolytic 
reduction  of  nitric  acid  or  sodium  nitrite  and  from  these  observatiom 
certain  points  have  evidenced  themselves  namely, - 

1.  The  reduction  of  nitric  acid  to  Hydro ::!ylamine  depends  most 
vitally  upon  the  maintainance  of  as  low  a temperature  as  possible 
preferably  15°  Centigrade  or  less, 

2.  To  obtain  the  best  results,  a continued  run  for  some  length 
of  time  after  the  last  addition  of  nitric  acid  is  desirable.  This 
might  be  further  explained  by  the  fact  that, 

5,  Hitric  acid,  when  present  to  any  great  extent,  in  an  unre- 
duced state  decomposes  hydro xylamine. 

4.  The  importance  of  adding  nitric  acid  drop  by  drop  to  the 
cathode  solution  instea,d  of  by  rapid  addition  is  fundamental.  This 
gives  a better  opportunity  for  the  total  reduction  of  the  acid  as  it 
is  dropped  into  the  solution.  An  accumulation  of  unreduced  acid 
verifies  conclusion  3. 

5.  Reduction  occurs  only  in  the  immediate  vicinity  of  the  cathode 

electrode  and  not  through  the  entire  cathode  solution  as  is  sometimes 

/ 

suppo  sed, 

6.  Illium  can  be  used  successfully  in  the  electrolytic  reduction 
of  nitric  acid.  It  has  a sufficiently  high  potential  when  in  a 50  ^ 
sulphuric  acid  solution  to  warrant  its  use  for  a cathode  electrode. 


1 


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-18- 

VI 

Eitliography 

1.  M.  A,  Besson,  Comptes  Rendus,  152,  1850  (1911.) 

2.  Ezio  Comanducii,  Chem.  Zentr.  I,  1530  (1909) 

3.  J.  Tafel  Zeit,  Anorg,  Chem.  31,  289,  (1902) 

4.  J.  Tafel , Perkins  ’ Electro  chem.istr\’  , p,  222 

5.  E.  P.  Schoch  and  R.  H.  Pritchett,  J.  Am.  Chem.  Soc.  V 38,  2042 

(1916) 

6.  Divers  and  Haga,  J,  Chem,  Soc.  VLI,  660  (1887)  Trans, 

J.  Chem.  So C.  V 69,  1665  (1896)  Trans. 

7.  Paschig,  J,  Pharm.  (5)  21,  245-246 

Abstract  in  J.  Chem.  Soc.  V.  58,  558  (1890) 

8.  T.  P.  Boehringer  and  Sohne,  Chem,  Zentr.  1,  1C6  (1903) 

Chem.  Zentr.  II,  313,(1902) 

9.  P.  B.  Ahrens,  Handhuch  der  Elektro chemie , 34  6,  (1902-3) 

10, Otto  Plaschner,  Monatsh,  V.  28,  235  (1907) 

11,  S.  V/.  Parr,  Brass  World  and  Plater’s  Guide,  457,  (1914) 

12,  S,  W.  Parr,  Chemi,  Abstracts,  3204,  (1915) 

13,  S.  W.  Parr,  J.  Soc.  Chem.  Ind.  Il6l,  (1914) 

14,  S.  W.  Parr,  J.  Soc.  Chem.  2515,  (1915) 

15,  Allmand  Applied  Electrochemistry 

16,  Eickhoff,  Amer,  Chem,  J.  28,  202,  (1902) 

Maxwell  Adams,  Amer,  Chem.  J.  28,  202,  (1902) 

17,  Hollem.an-Walker , Textbook  of  Organic  Chem.istry  206,  368,  409. 


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